ADSP-BF537 Blackfin Processor Hardware Reference
7-3
Parallel Peripheral Interface
The
PPI_CLK
pin accepts an external clock input. It cannot source a clock
internally.
L
When the
PPI_CLK
is not free-running, there may be additional
latency cycles before data gets received or transmitted. In RX and
TX modes, there may be at least 2 cycles latency before valid data is
received or transmitted.
shows the pin interface for the PPI. Enabling a particular pin
involves writing to the appropriate
PORTx_FER
register and, if applicable,
the
PORT_MUX
register. To configure for particular PPI pin usage, program
the
PORT_MUX
,
PORTF_FER
, and
PORTG_FER
MMRs as shown in
.
The 16 PPI data pins are found on port G. The upper data lines are multi-
plexed with SPORT0 signals. While 8-bit PPI operation still enables full
SPORT0 functionality, 10-bit PPI configuration disables the secondary
data signals of SPORT0. If 13 or fewer data lines are required for PPI
operation, the transmit channel of SPORT0 remains fully functional. The
three control bits
PGSE
,
PGRE
, and
PGTE
in the
PORT_MUX
register control
this granularity of signal multiplexing.
The PPI clock and the three PPI frame sync signals are found on port F.
The
PPI_CLK
not only supplies the PPI module itself, it also can clock all
of the eight timers to work synchronously with the PPI. Depending on
PPI operation mode, the
PPI_CLK
can either equal or invert the
TMRCLK
input.
The three frame sync signals are multiplexed with the three timer signals
TMR0
,
TMR1
, and
TMR2
. Timer 0 and timer 1 are internally looped back to
the PPI module and can therefore be used for internal frame sync genera-
tion. If
FS1
and
FS2
are applied externally, timer 0 and timer 1 must
disable their outputs by setting the
OUT_DIS
bit in the
TIMER0_CONFIG
and
TIMER1_CONFIG
registers, when working in
PWM_OUT
mode. Only the third
frame sync input
FS3
, if used, must be explicitly enabled in the
PORT_MUX
register by setting the
PFFE
bit.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...